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报道了从3-甲基-2-氨基苯甲酸出发一锅三步合成2-氨基-N,3-二甲基-5-卤代苯甲酰胺的方法.3-甲基-2-氨基苯甲酸(1)与固体光气反应生成中间体8-甲基-2H-3,1-苯并噁嗪-2,4(1H)-二酮(2),化合物2与甲胺水溶液发生胺解反应生成2-氨基-N,3-二甲基苯甲酰胺(3),3再与氯代丁二酰亚胺(NCS)、溴代丁二酰亚胺(NBS)或碘代丁二酰亚胺(NIS)发生芳香亲电取代反应生成目标产物2-氨基-N,3-二甲基-5-卤代苯甲酰胺(4～6).整个反应过程不需分离中间产品,最终产物经减压浓缩除去有机溶剂后,直接从水中析出针状晶体,总收率达到87%～94%,较文献报道的分步法收率提高30%以上.该方法工艺操作简单、反应条件温和、反应时间短、收率高,是一条环境友好的绿色合成路线.
A method for the synthesis of 2-amino-N, 3-dimethyl-5-halogenobenzamide starting from 3-methyl-2-aminobenzoic acid in one pot was reported.3-Methyl-2-aminobenzene The formation of the intermediate 8-methyl-2H-3,1-benzoxazine-2,4 (1H) -dione (2) with formic acid The reaction produces 2-amino-N, 3-dimethylbenzamide (3), 3 followed by chlorosuccinimide (NCS), bromosuccinimide (NBS) The target product 2-amino-N, 3-dimethyl-5-halobenzamide (4 ~ 6) was generated by aromatic electrophilic substitution reaction of imine (NIS) .The intermediate product was not separated in the whole reaction. The final product After concentrated under reduced pressure to remove the organic solvent, the needle crystals precipitated directly from the water, the total yield of 87% to 94%, compared with the reported fractional step yield increased by 30% or more.This method is simple process, mild reaction conditions , The reaction time is short, high yield, is an environmentally friendly green synthesis route.